This invention relates to the field of abrasive grinding devices, and in particular to abrasive disk/wheel mounting members.
Abrasive disks are often used in stock removal, typically in two steps. A large abrasive disk, with a firm backup pad, is used first for primary stock removal. A much smaller disk, with a softer more contouring backup pad, is then used for final stock removal and a finished surface appearance. The primary disk is relatively large, generally larger than about 5 inches in diameter; an exemplary, commercially available primary disk 100 is illustrated in FIG. 1A. The primary disk is mounted to a drive unit (such as a handheld, air powered grinder, not illustrated) with a mounting bolt or a retaining nut which is either passed through a center-hole 102 in the primary disk 100 or affixed to a threaded bolt attached to the grinding machine and passed through the hole 102. The hole 102 is typically surrounded by a bushing 104 or other reinforcement. FIG. 1B illustrates one type of retaining member 106 having an opening which has internal (female) threads 108 to engage with an externally threaded (male) rod. FIG. 1C illustrates an alternative retaining member 110 which has external threads 112 to engage with an internally threaded opening.
The secondary disk is smaller than the primary disk, generally from about 1.5 to about 3 inches in diameter; exemplary, commercially available secondary disks 202, 212 and 222 are illustrated in FIGS. 2A-2C, respectively. A less commonly used secondary disk 232 is illustrated in FIG. 2D. The secondary disks 202, 212, 222 and 232 mount to the drive unit in several possible ways. Each includes a mounting member 204, 214, 224 and 234 secured to the respective secondary disk 202, 212, 222 and 232. The mounting member 204 of FIG. 2A includes an externally threaded bolt 206 secured within an opening of the mounting member 204. The mounting member 214 of FIG. 2B includes an internally threaded opening 216. The mounting member 224 of FIG. 2C includes an externally threaded rod 226 affixed thereto. And, the mounting member 234 of FIG. 2D includes two or more clips 236 affixed to the surface of the mounting member or formed as an integral part thereof.
Because of the different mounting schemes and the different sizes of the primary and secondary disks, primary and secondary disks are not directly interchangeable on the drive unit, nor are different secondary disks directly interchangeable. Therefore, in order to switch between two disks, an operator must remove a securing device, the mounted disk and the disk backup pad from a drive unit. The operator must then mount the subsequently larger/smaller backup pad and corresponding disk onto the drive unit and secure them. FIG. 3A is an exemplary prior art disk backup pad 302 to which the primary disk 100 may be mounted using an internally threaded mounting bolt 106 (FIG. 1B) to mate with an externally threaded rod 304. Additionally, the secondary disk 212 may also be mounted to the backup pad 302, again using the internally threaded mounting bolt 106, if the diameter of the backup pad 302 corresponds to the diameter of the secondary disk. FIG. 3B is an exemplary prior art disk backup pad 306 to which the primary disk 100 may be mounted using an externally threaded mounting bolt 110 (FIG. 1C). Additionally, the secondary disk 222 may also be mounted to the backup pad 306, again using the externally threaded mounting bolt 110, if the diameter of the backup pad 306 corresponds to the diameter of the secondary disk.
It would be desirable, therefore, to have a common disk mounting system suitable for use with both primary and secondary abrasive disks of various diameters and accommodating various mounting methods.
An abrasive disk mounting system and a grinding system are provided. The mounting system permits both primary abrasive disks (typically having a diameter greater than about 5 inches) and secondary abrasive disks (typically having a diameter from about 1.5 inches to about 3 inches) to be mounted to the same backup pad and hub. Additionally, the mounting system permits abrasive disks to be secured with either a male or female threaded mounting member, or with clips or head caps, to be mounted to the same backup pad and hub. The grinding system permits an abrasive disk or a backup pad extension to be quickly and easily secured to a hub.
The grinding wheel mounting system of the present invention may be used with primary and secondary circular abrasive disks, the primary abrasive disks having diameters larger than the diameters of the secondary abrasive disks. The mounting system comprises a circular backup pad having a diameter approximately corresponding to a diameter of a secondary abrasive pad and having an opening centrally formed therein and a cylindrical hub secured within the opening of the backup pad. The hub comprises a first end having a first set of threads for securing the hub to a drive unit, and a second end having a face to which a grinding disk is mountable. The second end has a second set of threads internally formed therein, sized to receive male threads of a first type of mounting member to secure a grinding disk thereon, and a third set of externally formed threads, sized to receive female threads of a second type of mounting member to secure a grinding disk thereon.
The grinding system comprises a first abrasive disk having a plurality of equally angularly spaced head caps on a rear face thereof, a circular backup pad having a diameter approximately corresponding to a diameter of the first abrasive disk and having an opening centrally formed therein, and a cylindrical hub secured within the opening of the backup pad. The, hub comprises a first end having a first set of threads for securing the hub to a drive unit, and a second end having a plurality of equally angularly spaced recesses formed in the face sized and shaped to engage the head caps on the rear face of the first abrasive disk. Consequently, the first abrasive disk is mountable to the hub by causing the head caps to be engaged by the recesses in the second end of the hub.